A good article should offer a complete solution to a reader's quest. If there is any worthwhile, additional information, you can link to it at appropriate places in mid-text, or at the end of the page.
That's the basic premise. After all, you want to keep your reader on your page - from start to finish. If your reader clicks away too soon, Google may think he lost interest (= your article is no good). That has a negative effect on your page/author rank (high bounce rate).
Most authors place early links only because they're afraid the reader won't scroll down and see their ads. A better solution would be to write an exciting article.
Others want to create backlinks to their lenses and hubs. However, those are worthless and counterproductive. Google knows that it's you who creates those backlinks. How should your own backlinks attest to your authority?
So, don't send your visitors away. Lasso them in, tie 'em down, delight them ... and then let them go with a call to action (link) as useful as your article.